1. Field of the Invention
The invention relates to a reinforcement method for reinforcing bars in building construction, especially to a double winding reinforcement method and the product made by the method.
2. Description of Related Art
A reinforcement structure is mainly applied to enclose and fix main bars, thereby avoiding the main bars bending outward. Therefore, the main bars must be positioned accurately at bending corners of two ends of the reinforcement structures. Otherwise, the enclosing and fixing effect of the main bars would be affected, and this would decrease aseismatic strength of a building.
With reference to FIGS. 11 to 14, a conventional single winding reinforcement structure has multiple main bars 70, a reinforcement stirrup 80, and multiple reinforcement bars 90. The multiple main bars 70 are vertically disposed and arranged in a rectangular shape. The reinforcement stirrup 80 is wound around the multiple main bars 70. Each reinforcement bar 90 is horizontally tied with two opposite main bars 70. Each reinforcement bar 90 has a first end 91 and a second end 92. The first end 91 of each reinforcement bar 90 is wound around one of the main bars 70 and bent at an angle of 90 degrees. The second end 92 of each reinforcement bar 90 is wound around one of the main bars 70 at 135 degrees.
However, as for installing the conventional single winding reinforcement structure at a construction site, since each reinforcement bar 90 is bent at a fixed length, the multiple main bars 70 would be displaced as the construction sites differ. With reference to FIG. 12, the displaced main bar 71 is hard to be accurately positioned, such that one end of the reinforcement bar 90 encloses the main bar 70 but the other end of the reinforcement bar 90 cannot completely enclose the main bar 70. Therefore, the column toughness and effective enclosed area (area in dashed line) would be influenced, and the aseismatic strength of the construction site cannot meet the expected effect.
With reference to FIGS. 13 and 14, the reinforcement structure is applied in a laboratory. The main bars 70 can be precisely positioned, the first end 91 of the reinforcement bar 90 is horizontally wound around one of the main bars 70 at 135 degrees. The second end 92 of the reinforcement bar 90 is horizontally wound around the other main bar 70. The effectively enclosed area is larger than that shown in FIG. 11 and FIG. 12, but in the laboratory the reinforcement bar 90 is wound on the main bar 70 from top to down, which is hard to be practiced in a real construction site.